1. Field of the Invention
The present invention relates to a magnetic detector for detecting the motion of an object by utilizing a change in the resistance of magneto resistance elements.
2. Description of the Related Art
A revolution sensor of the gear proximity type, utilizing magneto resistance elements, has heretofore been known as disclosed in Japanese Unexamined Patent Publication (Kokai) No. 3-195970. This sensor is equipped with countermeasure against the occurrence deformation in the waveform that represents a change in the resistance. This technology will be described with reference to FIG. 18. Magneto resistance elements 21 are deposited on a substrate 20. On one surface of a support plate 22 is mounted a bias magnet 23 and on the other surface of the support plate 22 the substrate 20 is mounted perpendicular to the magnetized surface 23a of the bias magnet 23. On the substrate 20, the magneto resistance elements 21 are tilted at an angle of 45 degrees with respect to a magnetic vector (component B.sub.r in a direction perpendicular to the magnetized surface 23a) produced by the bias magnet 23. A change in the direction of magnetic vector B.sub.x accompanying the revolution of the gear 24 is detected as a change in resistance in the magneto resistance elements 21.
However, since the substrate 20 (magneto resistance elements 21) is disposed perpendicularly to the magnetized surface 23a of the bias magnet 23, the sensor is large in a direction perpendicular to the magnetized surface 23a of the bias magnet 23.